In the past, most eggs came from fertile hens. It was beneficial to the farmers because a fertilized hen’s increased hormone levels stimulate more egg production. Of course, fertilized eggs will also, in the right conditions, grow into chickens. In modern commercial egg operations, this hormone enhancement is achieved (and controlled), by artificial means through the feed. The eggs themselves are not fertile; they will never develop into chickens. While in the past, every bloodspot might have signified the beginning of a new embryo (safek sheretz ha’of), today’s commercial methods virtually insure that this is not the case.
It is in light of this modern reality that Harav Moshe Feinstein, zt”l, (Igros Moshe, Yoreh Deah 1:36), clarifies that blood spots found in commercially produced eggs do not present any fundamental kosher problem. With respect to fertile eggs in the past, where a significant doubt existed that the blood might represent a new embryo, it was necessary to throw out the entire egg if it had a bloodspot. This is also the reason why a minimum of three eggs were boiled at one time – if one of them had a spot, it would be batel b’rov to the other two. Today, however, the only concerns are maris ayin or dam beitzim (a small amount of blood from a broken blood vessel in the hen, which is not forbidden). As a result, the entire egg is never assur and mei’ikar hadin removal of the blood spot would suffice. Moreover, since the issur is not intrinsic to the egg, there is no problem with cooking a single egg in a pot. Rav Moshe, however, writes that it is a proper practice to dispose of the entire egg even today, as eggs are not expensive and a person does not incur any significant loss. Therefore, the requirement to check each egg remains in effect, as does the requirement to dispose of eggs containing actual blood spots. Nevertheless, in cases of doubt, difficulty or error, eggs are kosher, even if checking was not done properly; moreover, if blood spots are discovered during or after cooking, there is no problem with the preparation utensils.
Note: Fertilized eggs are available in the marketplace and are sold at a premium. When purchasing organic or natural eggs, a consumer should be careful to check the carton and/or contact the egg producer. Consumers wishing to consume fertile eggs should consult a competent Posek for guidelines. Some kashrus agencies will not certify eggs that are intentionally produced as they were in the past, because of the halachic complexities pertaining to those eggs.
When is Checking Required?
The accepted practice is to check each individual egg prior to use.
• If checking is overly difficult, such as at night on a camping trip, for example, where there is no available good light, one may eat eggs without checking.
• There is no problem with eating eggs cooked in the shell (boiled or roasted), even though these cannot be checked.
If one is in doubt whether the eggs have been checked, it is permitted to eat the food.
Blemishes Found in Eggs – What am I Seeing?
Commercial eggs undergo a screening process called ‘candling,’ which identifies eggs that are blemished. Despite candling, a small percentage of eggs found on store shelves still have various blemishes. This is especially pronounced in eggs with colored shells (such as brown eggs). Some definitions:
• Protein Spots: By far the most common blemishes found, these are formed by a microscopic “seed” of foreign matter that enters the egg during the early stages of development. Though found in both brown and white eggs, they are more prevalent in brown.
o Generally, these look like thick clear jelly in the egg white and may be any size. If the “seed” speck is visible, it looks like a reddish brown piece of dirt at the center of the spot.
o When appearing on the egg yolk, one generally only sees the “seed” speck.
Whether in the white or yolk, these blemishes present no halachic concerns and the eggs may be consumed without further action.
• “Blood” Spots: Far rarer than protein spots, these generally appear in the egg yolk. When the egg is released it breaks through a membrane containing a large blood vessel. Sometimes, a small amount of blood ends up in the egg. However, this dam beitzim is not forbidden. The spot will actually look like a drop of blood: red in color with a uniform round shape. When seen, the egg should be discarded.
o If noted after cracking several eggs, the eggs without the spots may be used after the egg with the blood spot is removed.
o If the eggs are scrambled prior to removal: If the spot is visible, it should be removed. If not, there is no problem with going ahead and cooking the batch.
o If the blood spot is noticed after cooking, the individual egg with the spot should not be eaten. However, there is no problem with the utensils or with other eggs cooked in the pan.
o If separating the egg whites and yolks, if one notices the spot after the white is separated and mixed with others, there is no problem. The yolk with the spot, however, is discarded.
• Greening: When eggs are boiled for too long, the yolks will often turn green. This is not an indication of any issue and may be ignored.
The vast majority of commercially available eggs are not fertile. While it cannot be guaranteed that no eggs are fertilized, the incidence is so small as to be halachically insignificant. Therefore, while, as a matter of practice, we are careful not to eat eggs with blood spots, no fundamental issur is associated with blood found in commercial eggs (unless specifically sold as “fertilized” ) . Moreover, most spots found in eggs are not blood spots and present no halachic problem whatsoever. That said, the position of the Rema to check every egg, as reiterated by Rav Moshe Feinstein remains the accepted and normative position. OU restaurant and catering policy is to check all eggs.